SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '761974cfc58252cdedbb4ab24623e5e7ab26b818301266830d096ae7762c0fdc' 
  AND token = 'rDdyQMNIY3WAmBFwSL/6WJZzX7dHeyHkIezspIj/PrQ=' 
  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"
    }
  }
}