SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfc2499fd6914acc1cec9f79b9bcde76595b43ad09f89b46c4761f29af134c53' 
  AND token = 'xhNQf1hlqtHm+VhYIN/cCflPbUmx0gNnUXYEIbekfxA=' 
  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"
    }
  }
}