SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '949a73e13718e0b9284e725f750b1db4577bd6aa9c8e79e0377576647d3979a3' 
  AND token = '929+6IFp2nxhn+lHeOX4KOh7lsHtl8IcLUqT6zOSyhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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