SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5f448699339ddd1e0b44ab6143cff1b8f75eca18f8c930044029ea84281207e' 
  AND token = 'U08zbRFJpURkcPHVm26CdaclZZKsXVSvQr5s2xU1AiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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