SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29e3c282e3f22208a1c204ea335e31aadd6d577391ea5199ae7285306daf1d62' 
  AND token = 'Nd12gNxWO/KLOefKNF95U0BdTXAjSnpP8VzhStcSDxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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