SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6640f8ce99f24b93b4f1b6e33c65fb6439b829362e5ce880fb7eaee972879d0a' 
  AND token = 'pBTpp5icntrxCCTvmv/2Byp1XeeKNHqIlVLuWOWi7oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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