SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99d309371b04c767627a73b3754e0397e8c6ee985fbf3e2d69331df9a611566f' 
  AND token = '/qvOoI/5wt+6xDFgZ2NPhmf5ROiUqkMzCC8X7H8zTEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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