SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fedf4fbeb1abeaf4736e0c37d2550959129427794f1f4c170ce9c40bf1de6b44' 
  AND token = 'GgDcly59wt4VUUMbhlMwTFC6XKO0BnrHbxMXCd/ha6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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