SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1447c4b8e923ca014e24a23af03bf5881b7c360c8ba00a4e40dab6730d158519' 
  AND token = 'lgmT8FAJczlViZ444K7QhjRd9b9uKAfgzKWuNewkFIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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