SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78d341e1f803c2f6295a3a4fe51aeecebff7353546012943af2cec329ca93a40' 
  AND token = 'XpTPKLR/0f7Mx1+ViU/Ljav1hYGiZHdGxQ3FvRZ/KTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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