SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7f0ac6896f2853065d232a48a9aee07666f009ec3e716dccca4ef6874ab09be3' 
  AND token = 'UmIwhlvV5CWqf2UhAAaJZyCwQJ+AagQZYwnc36tvbIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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