SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2b418964c7a6db01438a2874ebcf80724a86f6bc69d790df27f5af797acfda2' 
  AND token = '3BruKdR7amYFbIZPhfmhj6VT9MJguKZcIKPJcWtYUig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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