SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d6b708c63a6ab5284008a365f01ffc57f87681d74af80efceec396ba416e2e4' 
  AND token = 'AK8qX+eVqJUInWIHCXLnlqowrDLUIyG8TODvEdIHAw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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