SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99c7bd04fd014b6670853d5ce1c1000653f10ab067a391ae6b8093510b208b95' 
  AND token = 'H10m8x94vZH+gSKxPzGMdo4ZYgDgF3CtN4GJRGrtzHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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