SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6074c8dbd0362e5710b41cf57b029027d23756288549bfa405f7a5cf6547e50c' 
  AND token = 'W4UlfRVZgfllWaGuwJwKUKAbeD1+WPZaelQMiJhn/GE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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