SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e81c549f7867b70027569a172c81e35ee19e79989ff067bc018d9e879c6f0047' 
  AND token = 'dIbAkqoT1tOKp8KKTWF6c1BPn4BQOMnIxLIQ4WVBu3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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