SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6874ebb24f4743f5e19916cbeab6ccdd7c1fe87f15e2d2d20f7a7b4acaaea325' 
  AND token = 'Sye/Zr24jYNpaCYYUUxj/iLYRysbsbmYGXBtvEwOpEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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