SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66f996f795b0b0ef48eedf94722f6aaac27196ddd2aece0e8645c41c5a942572' 
  AND token = '/Twteoob/c1rZvltDbxnnEdj0IWC7kD8MfwQBUTD0Eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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