SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86de37b9de7ae21e9e80057823753886f6c67ef5c35456a06c31800820253b8b' 
  AND token = 'XUEpwfLXySVBvk4QAH7KIjAXm5b+f6DPLKkcy22/K3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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