SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bb189347b9cda6f32148056c00f09eb5327dad17c22e33d4595e0f0ae2fb1c4' 
  AND token = '+DD5wQPV4lsXrDu5ZTatEKvUddN4GQx1HH9mbCApCbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}