SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c42d8c73ee60878ff0981e2c0faf1f7bb5d7fc48b8e1ba6e2dda8d8477e1814c' 
  AND token = 'dr8JYuBec98MN+0UKsxCNgr3Hp6ehH0LlV5jenzZVLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}