SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f816175c9133c67ed2c0b8eb31b5d3bb8084ecac2b94b38b0e7765e1a0643d93' 
  AND token = 'z6/oyjOiONsHrgz0CAcg9O9tYEEl1kaQ7DzgtA98VOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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