SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f9d7f2849f4fbf8840f3aa9b4ea010a5b6595b38b803c8bb8932adcfc117621' 
  AND token = 'OCYkzy4zZ1u3vU+1C/2k1KeYMHdGa56V/h6ZwVC2w+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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