SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daf86d7c080c4efe13e7919f7b14ab9cd7b215dac3faf7f944bd068ecf286d03' 
  AND token = 'DfeJOpuyZFVq3ddBUb9OmL1PhGPhmiEIgsLJwE96/Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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