SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a572bb0c89bf10c04b5f31b88c01a875af9b56cbbeeb2dd30a9af4273c25b51' 
  AND token = '25/OM/egFuksUTV+zAe45EwPT43qkaM70ae+36Iwz48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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