SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58928604b79474d0bed5f7058d437faec77ab9fb621f3c534c4aa765d984b43c' 
  AND token = 'G+jKYdmCISoAxq/raBMM5HAjZXaE3X+8lxvXhsWDd24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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