SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dede65801de5652e880d6b0bbe8c5237171273310733e7f06151fbb297200b99' 
  AND token = 'rqRtfk106EgzED/IPZ05BphDqBDcpNaVGJFDvDgVYKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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