SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e3448beeea1912d7f7f7b8858577728c4ad36154d8d60ac0b031d2bd15f4231' 
  AND token = 'HGoOC30tns30HpELSxXmZgEa9wYABJL/gM0/5vNJM+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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