SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f7b776c80ea420821971a4f35215dcd22303b7dfed5290ac7e160d72c82a666' 
  AND token = 'eZtB1GOgrWes/+sHf2oJIeTgiJVjtkrfx+H1FetRR6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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