SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29b1552f24d442fca632afcff9828862d9c90ec15c0f7984655dcb02b6e17a83' 
  AND token = 'h3WRqtrKsNPBZFVx9c4sp5KLvLRtUJU8GRP6jd6/V50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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