SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ffe46c7cf1e60578aefdcdc992b1632e4a5471519e5316098be0b1407a19e5c' 
  AND token = 'V91cZsZO+a7wogiqJ/CWN9SnMumwBC8lG/KHs+wFzbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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