SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '405757e928322b08c644d9880441572d88aaf744d9713e088a449339167eb48f' 
  AND token = '26pSkQT1YThgSlU9rNoFvVkHXCFmdxBvCEB8S2mbPvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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