SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c0e0055e9c2942bcd22502ac684706c7d42c8159f2bdb75878bf714e5fd40a' 
  AND token = 'BlfVhGa0gb+5CYQv+VaF9b0J4Cf6n0uw2idQSL7/QMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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