SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3fc0e2155d260d7f0f31a437921b6264c86f7a817a8588f319b6a6076fa9c2e' 
  AND token = '6saTQrxG/YpCjntyuhZWjXodSaQU8Y0yrbaoWQYTIQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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