SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aa850707db24bb45bfa48e061b43894394d6e353a5ad1624c538124856dbb81' 
  AND token = 'HpiFq7aq+dQZwEtqmn4ihWg3csO0Rewk5+6OD3McJcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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