SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aae3609c733d93b831fbdc837cab744d231fc51daca45eb7e6746a59c362d364' 
  AND token = 'PLV0HTUIbIllgBnnUKTpFpuJvmQgnQLYgT91O+AeuoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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