SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4abf3349d39378939d27313d1454a66109b7c6db0b6c802b3659d23bb96549f' 
  AND token = 'B1AGTJHY8lfT1fvWGTNfZKkt0j/jfniF4qwYYO7KF24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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