SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4ecef48038a14721e4d882a421d596bbc653312dd3cf26aacbe6fb25bd6d70a' 
  AND token = 'sjvl/+xRn1GyXOPraQQWaD4vqo+w8/rzhnTI+uflxwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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