SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b528104f83127423a5d343aac7569ff43a9af804bd74b86241b87e1c3a4b183' 
  AND token = 'BGOQur8yQjkMt2/S9YCyQf1IOlLLJy69iNYPq+VdPGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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