SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a6143a80b89f7dc5ded146ed278d57c3c9a51d66e510278c348b17634fa5395' 
  AND token = '2o+RFcqqIhxhqBlC4RYWz2cOOobSnU4IRO/MVJIHnFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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