SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0b69554d1f4f4eb83754b9badccdd78ebac406f0d73d8bf79f425843e2558a7' 
  AND token = 'YTl6GZRv1IncQ6gvVhLD9PWd70ugiVzCRuDEnhnEX1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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