SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44abb43dffc4083d3a6298535954630b6c196f0c4614b9287aa5fc0715da75ef' 
  AND token = 'RcSFQaNpcLYPCbXz5BsVBCmUhnBwJSnI5ROGJg60vHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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