SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e83e4f42efbdc0b2b7a9e3c932326f83a1454b1439c8696055995a662d0c0b03' 
  AND token = 'BdiPDdRxiPWozYM9C5SESvPqMzIsOjXF885YBJ0sG7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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