SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99e07dc7da6842d05f2b7f8a782525864bc77cfe0f5d49c734f9bd585086b0ed' 
  AND token = 'a/WE8XbrneXEgQoyikNRIyIE/x7+YtZ5849OyItD0gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}