SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da52f401e913a8e94fd37460f2d81acbfe6f17f5e0488fce20edfe5b6f155843' 
  AND token = 'ComEPWZN3rA5VuRsklW9gFflfNW+S5h1FxcTl4AUZ8g=' 
  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"
    }
  }
}