SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08340074b86a460a88501127926bbd03d4fbefeec76059faeaa940fa3d7b295c' 
  AND token = 'nSIblS08U0P8Hw0J01YPPMwxQDzqCIpJ1+mF93Rjmmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}