SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffd6f6f3a45baf18d60e754a2b44fe17bceebd2cdab3969da5d863f2f6801af2' 
  AND token = 'Ud45yWariGsvqLXr/YxcsEUSn4aRtPLkiK8uWuQEX+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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