SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bfa1b6cd1ce30401b5cf9f4f9362b7ddeb392b82225afdebdb1aba6acb14e83' 
  AND token = 'XqWjxovmSyrihNti7aeYrJh0le35lT6h8F+2LKXFQD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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