SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ecc501f19e3acde3253afb2564ec0d97daa6302690f09b9e3819eeea4242d43' 
  AND token = 'xRwWn3rkm0AnVpHlCYRsUuwe4GLx6VXUj64OYueokoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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