SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df7c6e3431e17a5d7f9b0feab00acd8da12769daad8c3b1032455b4fb858fb73' 
  AND token = 'mrIxBf9fDNieRUorcSEBYbtvGQxD5ebUWx//WkstPo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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