SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc8e61b09ecf8b56e99c4f83e80ab1c1d2bbbcb1bb817c7c975281146df4a2b' 
  AND token = 'NvXad40vjBO/CRiQLYuCqin6Pq9IXmdj7rxUXRwPaRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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