SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510a30e9ccb25655bffd3c3a62d0aedcff64e397db10880133f96a32484100ba' 
  AND token = 'yPmuqwsekYhjuUfFnmZZFU7NGSb2vJNDADm1YFnYcwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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