SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bebcc3690b51bc67476f6f3f03e2c204341f65f27a2ac93a8552578b74eb31b1' 
  AND token = 'i5ERQPAWCQG3Xzeq8LaHdl1AE8Xp0Jv6CAbMEiz6yBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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