SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c8e19cbdf77198860df5d3a5a623c45304db7eb4d810b0e918528c628ea6493' 
  AND token = 'UFM3aGdnovyWvCb8SU04kexCwDr84ykT4jAac06Ln3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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