SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1dd670f61c56bca3f0e9868f238827874fd4eaf18d9d992e86f9f04a54f339b' 
  AND token = 'MqhfaQxVSIPy58oXqydZ/qDknNYzIoAABJITHVV+wLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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