SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9260c958ef3b0e197107ad2842e50537d0729ccef4443ea91d550ec2c5575bbc' 
  AND token = '/7G8Jq+yqPB2C8N7HN0SGy4OhlpUFxPbFP07h9OxaK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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