SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453108799c7292473dc173d0a9875789152a6e451362c8f9d030428fad14b880' 
  AND token = 'tbrYtLfBsw2IZzl2HRuB4la/0WjmyEbBiiO88fRrywU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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