SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4121343c2de0dfef54daa1729be9c6f538311ec6a1aee878d7f93e72ae538eaf' 
  AND token = 'KhTlZxQRfrcqhXrsB6VjAKztoi26UcDddQdPQDj1MH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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