SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21886bbf8677a805cccf811a0a579e47f88f4dc0d3ac286bcd3cd29e154985d7' 
  AND token = 'GsOMBDDVjP6pqnc6Wgn/ekCLq7swHyCtjT3Ag72BhOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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