SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e461f07cd70896b87a2f81d9d36a587d7bf65d88c871960d4ecd50b02def2247' 
  AND token = 'K4T2GbtNADPd49HW9KRQNaTyYfh8XRzIEXuIVKSirY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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