SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac2ace764f1533a7059061aeff6754938b137a052c4cb85e7de6d27d23c9d28c' 
  AND token = 'qOAapN6mJlXSSWuaTXyrjBNkJnE+C1bH9a9IoMhCoR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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