SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dd9581e655e7bf87fe3827b3fe373748e2ddf2b8ee38d9c6e3a53a596ad1017' 
  AND token = 'GN5gNjcqAG+JqazmAsTNHFvPbpBQpjfVyawXnlegBmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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