SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7d7ca76250532c7de0a188917f83d659c58b3e60f55b4480e16445c7c412f25' 
  AND token = 'tqOGeyUDqV+unciURbKh2RrwLgTv2rPqc1mZ07FSl/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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