SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30b81871a30192d5feade17a1a9f0ee63b576984bd49910423cf4d1df34fa147' 
  AND token = 'K/2TE0jH/KZM1kG5+1kb/08OTuT3jXqVvNwHMy7DvWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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