SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '786c819ed3e2f7d7e4dd3fa769d4ba120dbe9629130bda4340f596051bffeb2d' 
  AND token = '4gCTEYcd00mpwxDDNRDyPH5ZhfXNT/G7jTxCjWngrko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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