SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '376c862569e7ee4d61543fd132050ee3f0f8480057e1ca272760754b4b4896cf' 
  AND token = 'TP5i/TOcGbbn1UKoqAZDao2yjKxmre8vKIEirw4QwMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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