SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '866f5787f0711507b2dc6fbcb5b144317f2be0e495b659fb708e2d09d7a23a70' 
  AND token = 'vuxugZcFugQ27DQqEHjNqEywu4FHaKS1YmJNSaDb/BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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