SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d44f9ef54ed05b319456867188cd435d182c2a5b20e5568999b2772c491b1c7' 
  AND token = 'RUde/uKahQK8iTKHiXUU0jvVSMWlGiCsusp02frGrOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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