SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7a9b0dfab41b1f22c0983337429408cd1c3a552422a312fbb4575589aae8cad' 
  AND token = 'dKXQ04HbH+0xisM5CwUClk4ZSzksYQyQTbktASfJXNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}