SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ff6b6ebf11bc0414caa29fb0106794dbb8e433eaf6d36199e6f09d94b3eddef' 
  AND token = 'DsXDFsnjL0HtCRa8/0OSXkzfgAQ+SQVUFw+5CYc3tTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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