SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b8b5b5029fddf377dcf244dd4b7d19a864370828efd3aeb748227de4a8748dc' 
  AND token = '1dx0NHk9LZH0eKR/nTPSxVFL28TOKi59kZiaKmljilg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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