SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1efd3ed7eae2d2aa2b7febb9d63e61ca8f31d54163961560e96ae31315e683fb' 
  AND token = 'tUDnY124GHvHl3nWCAtPD+zh6WkyWpiPB6yeqExrlTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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