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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b103b02482e36978f63e5ce67857d9d24acfecf416a8aedc962b4ded682f52' 
  AND token = '+AOPDQj5yaDXhuwRWhVKTMMUvuthT51p2SNAA17mgIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}