SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b501227bf54a2bdb83a369a295fc586eff2d27011be4b39e5e76bbdc4457b608' 
  AND token = 'xP8Nhhh5B1/GkvDnJ4QP7At3fbHYImjXX11JP+TlMQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}