SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec198ce8f983e07ed81820fffd9a849b66b94dffcbad80e6e84b93cda5117d5c' 
  AND token = 'YXhSMYaXYPIjqQqUkR01gpE8+FAYnRxbluGDbVpURqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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