SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '779f84fb117fb9ca7e41a07843f02fdcd8ced6f3bbe9ea6b7cac56c93ff2ac5b' 
  AND token = 'lSNxoH8/JNGeUXmLr1CNcxaZsKP+C3vg/HAwTuGietA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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