SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1474c6bfc0f0598d5cd4482c8b734edf301ee90f9a2e047a41c607d5a919065b' 
  AND token = 'LH9qAS3+JAwEAvvCP/j9GWmuZwHxSKKZDfFZ+c3BC2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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