SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa92d534fcc22bfe73f3e9cce00f220188dafb523cfdc733becb2cd441334c39' 
  AND token = 'UACm0Cgu7PJ42+I3drgIW5pRzE+PqDSq33kQWTfQiWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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