SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c81225a44f32d12b166a5616d47236bcd8f705af3008388f3f0f77cff8f754' 
  AND token = 'CY0u/meY9JAg+ljBogZlOpF+xp6XIyFqEu1dGnhXE+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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