SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c74c10b94c1ce137c755bd5d53596b8cdeea7e1518fc8084b5564f8bb206af3d' 
  AND token = 'h0EdiTXo92FHWY6ZMFpdrCz05NWAB0G7xgiO2NdEp+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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