SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5819a678a9eab07204213a3564b906881dd94657bfc10f2e560258d3ea285a12' 
  AND token = 'iRL7lvlClqMwMz8MI9QxVLHSu2FrJAmSQQ/OhJ1gDak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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