SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a945344779d588e55280958a88aa92df97537945fe906cd1765955b7aae29b69' 
  AND token = 'x55Gye+THSzbcRLo9GFb9eqhnEbCgl/bR6YkaRbiFGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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