SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6123819c6b6ae5a8114fa70bf7dbc7892a5749ed98f3c2b61478bb737087d6d' 
  AND token = 'G99WJBaFdnyXAQuESksQ1IDwcSu/nmtpXB6MNQDCBhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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