SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91e8a1dbeecdc606adc792da9baee5da53c9d9c10dbb99177ede6f147dbba684' 
  AND token = 'wH0Z36KbzUToHITdZBUD6brKGor/cs+E00S6UEd18tU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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