SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38af3573890ab6631633fc586e3898b355bc323430c7f85880d17b75feb913d0' 
  AND token = 'CJGjrvI+NZIHgTbgKyNz5qDiTBdQc9F5CugQ2E9YF0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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