SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c17bbbf047585844be1e0ffa8caa82c3d55bdc2c2bf1b9a510bd1409ae376e0' 
  AND token = 'UBjdafamQCT0pmO/W9lgZ1oxcfrPWoUomsGxXXFsDd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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