SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '148407156b1e1fb51f5c89d523ca230a25988203cec3c6e6af0c58d625979207' 
  AND token = 'Ba3Qr7mX+FQy9BE4wA6EkT5WABXufyZASG4mRMc9UWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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