SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61f1bedbd8c599f5078b163b3c2c5ccff927bf677f5dae46d286b4437ba5755c' 
  AND token = 'WQ422Bg13CyK5Zx/LIVOkeGi+PJ8WAtBwc2xBHxE3ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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