SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '030d0b55bf57950a438a347513be92b84bcb74d5c6f486d93ad033aeff1cdb51' 
  AND token = '/B6XWVAOIUofSduq/OgpHRGsO7pgZvIZQzDyt1VRFWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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