SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c669491dee662f0d6f103809be82c78f654a53234b1e69cb43864973f4d2e5b8' 
  AND token = 'e1nDnCujP42Zi46bMQfQSY59vBQO+tlfbUAronfl5jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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