SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c4b4ada1a5ca1475aa75d4070bc56c940682947b01e6ab454cd3863d1c9f64' 
  AND token = 'PMVMjAPmZrJFuTZRDOg6oK9XTmkDCQjVqUuxNnJOT74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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