SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab89fe480e07e950920322e6bad246447f100ea650d8ff59d3259cdc57afcb9' 
  AND token = 'Sc58cHzQqkYJoBaxlPfstvVHwcolmJU8PmLOsDWltgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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