SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '834177d9a6c3c3884e5ef11299921a2738cf4a71057551c1ab99008b6513f966' 
  AND token = 'vMueFwdxHZcTJqezvHhW0qGKL4CHe6j2gt2UBnCQ4lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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