SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fd519d261f833d7bd7992dda291b87e13b7dd0c01d0c30a97938bd8d9c14fe8' 
  AND token = 'BTOCxKC4Gwk/AmMIV+hZr3Gji5A+1sd5xJVWuL6SppY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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