SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ba4ea4d7676b9d4a22b185da7343f4fc1e5f31bf14d22ea39eed8c5ae4d802' 
  AND token = 'q/V5vWYiQ4FLp/gWgorW+HlwKtV30sCmjMBi/Bk3c1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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