SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9786bc078ae6a4687b65b57e4f8dc4acad4f2c030fa399e4b812d09082c96289' 
  AND token = 'nZ4gbhLq7q1+omRl+cKrByb9p9Ja5UrC1X/tfqjY8Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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