SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29fa32e43671166f5354c6564fffd0fea9ba14edd6524a606dc2c7599baf7644' 
  AND token = 'jjYVpPNQaiOTThWp93NA1DHGZHRVYyatnZ02HCt3n+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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