SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ba20042b0fe3ed0146c830cd8b1ae8de96875a9fa3519c3510e92aac9a72a27' 
  AND token = '8QTLByQ51iroy0O4FekP3DjPdmdGqq35ZH5w1ln3Y8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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