SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efcc5db913d8cb12c498687500f3fd3ca9a99051f4d1ab4981f4ae7ded0d33ed' 
  AND token = 'dr/Tleh24hBGxX2/j1oDGvzYstWAlSOTnbrgEaKHNhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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