SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75c960a7ea17ef7385571f4670e60b00d44dd464cf6193d5d2632330b58bffea' 
  AND token = '+EMbdnZam/fJ0z8GdxzwpCJpYpBlRxjdd7YqjTYX5CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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