SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3071de5f572516ad82117ee84f954609e1469ddb67756669d8ab289627d258fb' 
  AND token = '4RgMbFt//frA6YiS0xvW4ShNHq5pjX+KaNBcFTLt95I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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