SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b86ba1803600023d7755d5aa1f23278306ee8defc851f83a4deaa790771639ea' 
  AND token = 'yrRiqZFx2fO8BnYFl0rp13x/PohrguOr+kdx5UvMdRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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